Meeting Abstract

P1.41  Tuesday, Jan. 4  The Role of Matrix Metalloproteinases in Phagocytosis in the Caterpillar, Manduca sexta LINDNER, K.L.*; RUBALCAVA, J.; HARING, J.S.; GREENLEE, K.J.; North Dakota State University; Northern Arizona University; North Dakota State University; North Dakota State University kimberly.lindner@ndsu.edu

The host defense of insects is a complicated process that involves many different, but interconnected responses. They can be classified as humoral, such as the production of anti-microbial peptides, or cell-mediated. Cellular immunity entails responses such as encapsulation, nodule formation, and phagocytosis. Because phagocytosis requires cleavage of surface proteins by proteases, we hypothesized that matrix metalloproteinases may be involved in this process. Matrix metalloproteinases, or MMPs, are a family of zinc-dependent endoproteinases that have a variety of roles across species including physiological and developmental processes. These consist of tissue invasion, tissue repair and remodeling, molting, and various immunological functions. MMPs are important in proper immune function since mice without MMP-2,-7, or -9 have higher rates of severe infection or mortality compared to control mice. Even with these known functions, the exact role of MMPs in immunity is still uncertain. To further understand the role of MMPs in cellular immunity, we used hemocytes from Manduca sexta and incubated them with fluorescently labeled beads in the absence and presence of MMP inhibitor. We used flow cytometry to quantify phagocytosis of beads. Preliminary data suggest that overall phagocytosis was inhibited in the presence of MMP inhibitor. Also, a decrease in the amount of phagocytosis of 4 or more beads was observed with the addition of the inhibitor GM6001. While these data support the hypothesis that MMPs are important for phagocytosis, it is unclear what the mechanism of MMP action is. Possible MMP-substrates include adhesion molecules or other cell surface molecules.